Intermodal containers can be used in general to hold and ship various materials, including bulk materials, and can be useful as transport containers for waste material. A primary advantage of intermodal containers is the use of connector fittings at standard spacings, typically at each of the eight corners of a rectangular container or box in one of several standard sizes. The connector fittings enable the intermodal container to be affixed to mountings placed at the same standard spacings on movable chassis configurations appropriate for road, rail, sea or other transport, for stacking and the like. Likewise, the containers can be manipulated using lifts and spreader frames having grappling devices at the standard spacings.
Advantageously, solid waste is compacted into a container of one form or another. Intermodal containers can be used to hold and ship bulk materials, and might be used to accumulate compacted material from a compactor. However, refuse containers for waste material, compactor containers and the like, need to be structured for rough treatment, whereas shipping containers are advantageously of limited weight. Also, shipping containers advantageously have one or more access doors, and access doors generally weaken a container structure in a manner that presents challenges for use with solid waste in general and compactor products in particular.
Intermodal containers are used in various standard sizes. A typical standard container is a substantially rectilinear box and may measure twenty or forty feet in length, from four to twelve feet high and eight feet to eight feet six inches laterally. The typical container is made using steel plate, optionally with channel-like corrugations, and may comprise reinforcing and framing parts comprising rectangular tubing, angle iron and bar stock.
One of the walls, normally the rear end wall of the typical container, is at least partly occupied by one or more door panels. In semi-trailer shipping container applications, two panels are pivotally mounted on vertical hinge axes journaled at the corners of the end wall. The panels lap one another at the midline of the container in the rear. For waste containers and other applications that advantageously have a heavier door or a sealing door closure, one panel may be preferred instead of two. The panel typically is hinged on a vertical axis and arranged to bear against a compressible seal. On the latch side (opposite from the hinge), a strike support can support the door panel in alignment. Clamping devices and be used to draw the door panel so as to compress and seal with a gasket disposed in a frame provided around the end wall opening, mounted either to the door panel or to the frame.
For solid waste handling and other demanding applications, the door panel, like the container as a whole, should be structured for rough handling, i.e., heavy duty and thus likely to be heavy in weight. Mounting a full-width single door panel on a hinge axis cantilevers the weight of the door panel on the rear of the container sidewall carrying the hinge, requiring structural support. Opening, closing and sealing the door, which preferably should be possible by manual operations of a single operator likewise is to be considered. The structural and operational requirements, versus the need for precision if sealing is also intended, reasonably total weight and the like, are challenging and sometimes inconsistent design objectives.
Access openings such as end door panels might be carried on a hinge mechanism defining a pivot axis along the frame at the side, top or bottom of the associated end wall. For human-operated doors, a vertical hinge axis has the advantage that it is unnecessary to apply force except to overcome inertia. For a dumping container, a horizontal hinge axis at the top of the panel advantageously can be used to permit the door panel to swing open when the container is tipped to unload the contained material by gravity. A sealing door panel preferably has a single integral panel as large as the opening, thus minimizing the complexity of sealing. Two panels hinged on opposite sides of the opening are possible, as are two or more panels with an intermediate accordion fold hinge. Various mechanisms can releaseably hold the door panel(s) in a closed position, typically involving a latching connection between the door panel and the frame of the doorway, at one or more points remote from the hinge axis. There are various choices that can be made, but adapting a door for one of the foregoing structures to take advantage of a given attribute normally makes the door less than optimal with respect to the other attributes.
Container structures vary depending on the cargo and expectations for loading and unloading. Shipping containers thus often are structurally different from waste containers. This it true even though both types are advantageously structured for intermodal shipping (i.e., in standard sizes with receptacle fittings at predetermined standard locations). Containers may also be arranged for roll-on/roll-off loading, tip-dumping using a forklift or tined overhead dumping collection truck, etc.
An exemplary container with intermodal standardized fittings is known from U.S. Pat. No. 6,364,153—Petzitillo. This container has a gasket sealed top cover that can be raised and rolled to tip open toward either side, and an end opening with clamps to facilitate a seal between a hinged end wall and a gasket mounted around the perimeter of the sealed end opening. The gasket material might be carried by the door panel or by the container frame, but in either case, the mounting mechanism for the door panel needs to be configured so as to press the door panel against the frame and thereby to compress the seal or gasket.
By providing a top opening and an end opening, the container in U.S. Pat. No. 6,364,153 permits access from the roll-aside top panel opening or the hinged end opening. The trade-off for having such openings is that the container must otherwise be structurally self supporting. The top panel opening in the '153 patent does not extend to near the top ends, providing some support in the form of stationary structures on the top wall at the ends. Also, the entire container is soundly reinforced with additional support framing and struts. It would be advantageous to include a set of plural door panels on a container in a manner that provides strength as well as access and contributes only modestly to the additional weight of the container as compared to a similarly sized container with fewer doors.
Although various containers exist for accepting, carrying and dumping contained materials in various arrangements, it would be advantageous to provide a multipurpose container that could be used universally for a number of different operations, and with a variety of different types of loading, unloading and access equipment. Such a container could accept loading materials from a variety of sources, such as bulk or waste materials from either of an end-loading compactor connection or a top loading dumper, having optimally placed doors or portals for each alternative, but being structured for adequately rigid and durable support of its shape and limited total weight.
An advantageous such container would be configured to facilitate unloading of contained materials in similarly versatile ways, including a dedicated dumping door. Preferably the dumping arrangement could unload the material loaded as described above, for example a compacted slug of solid waste, simply by tipping the container using, for example, a tipping chassis or a roll-off chassis transporting vehicle.
One advantage of such a container is that it could eliminate the need for the user to stock numerous specialized containers (e.g., separate containers each optimized for particular loading and/or unloading equipment or scenarios, thus reducing the overall cost of purchasing and maintaining an associated large inventory of such specialized containers.